关于羊水的描述下列哪项是错误()
A.妊娠前半期来源于母体血浆渗出液
B.妊娠后半期主要是胎尿
C.足月妊娠羊水800~1000ml
D.羊水呈弱碱性
E.保持动态平衡
参考答案:A
—Do you know that Jack()a postman for about six years —Yes, I see.
A. has become
B. has turned
C. has changed
D. has been